1. Field of the Invention
This invention relates to an apparatus for removing branches from treetrunks, which apparatus comprises a frame, which is adapted to be suspended from a lifting tackle and is provided with grippers for engaging the treetrunk from below, with a longitudinal feeding device for moving the treetrunk in its longitudinal direction, with branch-removing tools, which are spaced around the treetrunk, and preferably with a crosscutting tool, which is movable transversely to the direction of the longitudinal feed movement.
2. Description of the Prior Art
Such apparatus for removing branches are mounted on a suitable lifting tackle, which in most cases consists of a crane that is mounted on a separate chassis. The apparatuses for removing branches can skilfully be manipulated when they are suspended from the lifting tackle. When it is desired to remove branches from the treetrunks, the apparatus is lowered onto the felled tree with the grippers open. Thereafter the grippers engage the treetrunk from below and hold and guide the treetrunk for the continued processing. When the apparatus which has been coupled to the treetrunk has been lifted the feeding device moves the treetrunk in its longitudinal direction past the branch-removing knives, which face in the opposite direction and which may be secured to separate knife carriers or directly to the gripper arms. Branches are removed from the treetrunk all around its periphery as the treetrunk is pulled through the apparatus. When all branches have been removed from the treetrunk it may be cut to a desired length by a suitable crosscutting device so that felled trees can be stored in an efficient manner.
The pulling of the treetrunk through the branch-removing tool when the treetrunk is gripped by the grippers requires a considerable feeding power. The feeding means may comprise serrated coupling rollers or coupling chains (German Patent Specifications 28 11 660 and 28 55 430, Published German Application 37 12 302), which are caused to engage or embrace the treetrunk and to impart the required longitudinal feed movement to said treetrunk. But in spite of the serrations on said coupling means or of other means provided on said coupling means to improve the coupling between said coupling means and the treetrunk, relatively bulky branches or a relatively thick bark may often give rise to disturbances, such as a jamming of the treetrunks in the coupling means or a slipping of the treetrunk past the coupling means, so that a manual intervention will then be required, which will be difficult and time-consuming and will involve an accident risk.